The present invention relates to electromechanical transducers and, more particularly, to a cylindrical bender-type vibration transducer. The present invention includes a hollow cylinder having two layers bonded together, i.e., a cylinder within a cylinder. At least one of the cylinders is made from a piezoelectric material polarized in the thickness direction. By use of the cylinder within a cylinder, there is essentially no vibration in the longitudinal direction along the cylinder axis and symmetric vibrations are received or transmitted radially with respect to the cylindrical axis. This type of configuration allows for greater sensitivity. Also, the mechanical resonance frequency may be lower than conventional cylindrical piezoelectric devices of a similar length and diameter. The use of the two cylindrical components allows the same mechanical resonance frequency of the bender design to be specified for various cylinder sizes.
In an alternative embodiment utilizing a barrel stave type of arrangement, the operation of a transducer may be shifted and/or controlled by the manner of electrical connection to, or excitation of, the piezoelectric elements within the transducer.
Also by adding end caps, the node of vibration is changed, causing the resonance frequency to decrease.